stdnet.NewNet and NewNetWithDiscover ended with
return n, n.UpdateInterfaces()
handing back a non-nil *Net together with the discovery error. Three of the
five call sites (Engine.newWgIface, ice.NewAgent, SingleSocketUDPMux) logged
the error and kept using the instance, which is only safe as long as the
instance still works after a failed discovery.
That stopped being true when Interfaces() gained a lazily refreshed cache:
updateInterfaces sets lastUpdate only on success, so after a failed
construction the 30s cache guard never holds and Interfaces() returns an
error rather than the empty list it used to return. Feeding such an instance
to pion is worse than passing nothing at all - ice.NewAgent falls back to its
own stdnet when Net is nil, and the interface blacklist is applied separately
through AgentConfig.InterfaceFilter, so the fallback loses nothing. Instead,
a transient discovery failure (the Android bridge at boot, or an interface
disappearing between net.Interfaces() and Interface.Addrs()) turned into a
hard "error getting local interfaces" from ice.NewAgent, and aborted the STUN
and TURN probes, which never even need the interface list.
Since the accessors already refresh a stale cache on demand, the eager
discovery in the constructors is redundant: drop it, make both constructors
infallible, and let the discovery error surface at the call that actually
needs the interfaces. UpdateInterfaces had no callers left and is not part of
transport.Net, so it is removed along with it.
InterfaceByIndex and InterfaceByName read the cached slice directly and never
refreshed it, so they would have kept reporting ErrInterfaceNotFound forever
on an instance whose first discovery failed. They now go through the same
refresh path as Interfaces().
- Move `util/grpc` and `util/net` to `client` so `internal` packages can be accessed
- Add methods to return the next best interface after the NetBird interface.
- Use `IP_UNICAST_IF` sock opt to force the outgoing interface for the NetBird `net.Dialer` and `net.ListenerConfig` to avoid routing loops. The interface is picked by the new route lookup method.
- Some refactoring to avoid import cycles
- Old behavior is available through `NB_USE_LEGACY_ROUTING=true` env var
Deduplicate STUN package sending.
Originally, because every peer shared the same UDP address, the library could not distinguish which STUN message was associated with which candidate. As a result, the Pion library responded from all candidates for every STUN message.
riccardom